title: Childhood socioeconomic status and adult femoral neck bone strength: findings from the Midlife in the United States Study.
abstract: OBJECTIVE
  Bone acquisition in childhood impacts adult bone mass, and can be influenced by childhood socioeconomic conditions. Socioeconomic status is also associated with body weight which affects the load that bone is exposed to in a fall. We hypothesized that socioeconomic advantage in childhood is associated with greater bone strength relative to load in adulthood.
  
  
  METHODS
  Hip dual x-ray absorptiometry scans from 722 participants in the Midlife in the United States Study were used to measure femoral neck size and bone mineral density, and combined with body weight and height to create composite indices of femoral neck strength relative to load in different failure modes: compression, bending, and impact. A childhood socioeconomic advantage score was created for the same participants from parental education, self-rated financial status relative to others, and not being on welfare. Multiple linear regression was used to determine the association of childhood socioeconomic advantage with femoral neck composite strength indices, stratified by gender and race (white/non-white), and adjusted for study site, age, menopause status in women, education, and current financial advantage.
  
  
  RESULTS
  Childhood socioeconomic advantage was independently associated with higher indices of all three composite strength indices in white men (adjusted standardized effect sizes, 0.19 to 0.27, all p values<0.01), but not in the other three race/gender groups. Additional adjustment for adult obesity, physical activity in different life stages, smoking, and heavy drinking over the life-course significantly attenuated the associations in white men.
  
  
  CONCLUSIONS
  Socioeconomic disadvantage in childhood is associated with lower hip strength relative to load in white men, and these influences are dampened by healthy lifestyle choices.
authors.affiliation: Division of Geriatrics, Department of Medicine, David Geffen School of Medicine at UCLA, 10945 Le Conte Ave., Suite 2339, Los Angeles, CA 90095, USA. akarlamangla@mednet.ucla.edu
authors.forename: Arun S
authors.initials: AS
authors.lastname: Karlamangla
authors.forename: Takahiro
authors.initials: T
authors.lastname: Mori
authors.forename: Sharon S
authors.initials: SS
authors.lastname: Merkin
authors.forename: Teresa E
authors.initials: TE
authors.lastname: Seeman
authors.forename: Gail A
authors.initials: GA
authors.lastname: Greendale
authors.forename: Neil
authors.initials: N
authors.lastname: Binkley
authors.forename: Carolyn J
authors.initials: CJ
authors.lastname: Crandall
mesh_terms: D000368:Aged; D015519:Bone Density / Q000502:physiology*; D005260:Female; D005272:Femur Neck / Q000378:metabolism* / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D012737:Sex Factors; D012923:Social Class; D044465:White People
keywords: Bone strength; Childhood socioeconomic advantage; Femoral neck; Health behaviors